Need to show related products of simple product in configurable product

Question

I need to show related products block on configurable product page (as it is by deflault), but instead of related products of configurable product i need to show related products of simple products which are included in that configurable product.

Answer 1

If you want to display related products of child items instead of the related products of the parent item in a configurable product structure, then

Create a new module and override _prepareData function the main block file

vendor/magento/module-catalog/Block/Product/ProductList/Related.php

Something like

protected function _prepareData() {
    $product = $this->_coreRegistry->registry('product');
    /* @var $product \Magento\Catalog\Model\Product */

    // GET TYPE
    $productType = $product->getTypeId();

    // IF CONFIGURABLE
    if ($productType == 'configurable') {
        $childrenProducts = $product->getTypeInstance()->getUsedProducts($product);
        if ($childrenProducts) {
            $this->_itemCollection = array();
            foreach ($childrenProducts as $singleChild) {
                $relatedProductCollection = $singleChild->getRelatedProductCollection()->addAttributeToSelect(
                                'required_options'
                        )->setPositionOrder()->addStoreFilter();

                if ($this->moduleManager->isEnabled('Magento_Checkout')) {
                    $this->_addProductAttributesAndPrices($relatedProductCollection);
                }
                $relatedProductCollection->setVisibility($this->_catalogProductVisibility->getVisibleInCatalogIds());
                $relatedProductCollection->load();
                foreach ($relatedProductCollection as $singleProduct) {
                    $singleProduct->setDoNotUseCategoryId(true);
                    $this->_itemCollection[] = $singleProduct;
                }
            }
        }
    } else {
        // IF OTHERS

        // main FUNCITON CODE
    }


    return $this;
}

and then override the items.phtml file

vendor/magento/module-catalog/view/frontend/templates/product/list/items.phtml

under case 'related' change the if condition

if ($exist = $block->getItems()->getSize())

to

if ($exist = count($block->getItems()))